Circuit breaker is a kind of switch device which can control the mechanical current (carrying and breaking the current under the condition of abnormal circuit) under specified conditions. The main components of circuit breaker can be divided into molded case circuit breaker, miniature circuit breaker and frame circuit breaker. What are the construction and installation requirements and working principles of miniature circuit breaker?

微型斷路器施工安裝要求和工作原理介紹

Construction and installation requirements and working principle of miniature circuit breaker

微型斷路器施工安裝要求：

Construction and installation requirements of miniature circuit breaker:

1)斷路器的安裝應符合GB13955-92標準及產品說明書的要求。

1) The installation of circuit breaker shall meet the requirements of GB 13955-92 standard and product manual.

2)斷路器的安裝應充分考慮供電線路、供電方式、供電電壓及系統接地型式。

2) The installation of circuit breaker shall fully consider the power supply line, power supply mode, power supply voltage and system grounding type.

3)斷路器的額定電壓、額定電流、短路分斷能力、分斷時間應滿足被保護供電線路和電氣設備的要求。

3) The rated voltage, rated current, short-circuit breaking capacity and breaking time of the circuit breaker shall meet the requirements of the protected power supply line and electrical equipment.

4)斷路器的安裝接線應正確，在不同的系統接地形式的單相、三相三線、三相四線供電系統中剩余電流保護器的接線不同，應給以充分注意。

4) The installation and wiring of the circuit breaker should be correct. In the single-phase, three-phase three wire, three-phase four wire power supply systems with different system grounding forms, the wiring of the residual current protector is different, which should be given full attention.

微型斷路器工作原理：

Working principle of miniature circuit breaker:

微型斷路器由操作機構、觸點、保護裝置(各種脫扣器)、滅弧系統等組成。其主觸點是靠手動操作或電動合閘的。主觸點閉合后，自 由脫扣機構將主觸點鎖在合閘位置上。過電流脫扣器的線圈和熱脫扣器的熱元件與主電路串聯，欠電壓脫扣器的線圈和電源并聯。當電路發生短路或嚴重過載時，過電流脫扣器的銜鐵吸合，使自 由脫扣機構動作，主觸點斷開主電路。當電路過載時，熱脫扣器的熱元件發熱使雙金屬片上彎曲，推動自 由脫扣機構動作。當電路欠電壓時，欠電壓脫扣器的銜鐵釋放。也使自 由脫扣機構動作。

The miniature circuit breaker is composed of operating mechanism, contact, protection device (various releases), arc extinguishing system, etc. The main contact is manually operated or electrically closed. After the main contact is closed, the free tripping mechanism locks the main contact in the closing position. The coil of the over-current release and the thermal element of the thermal release are connected in series with the main circuit, and the coil of the under voltage release is connected in parallel with the power supply. When the circuit is short-circuit or seriously overloaded, the armature of the over-current release will pull in to make the free release mechanism act, and the main contact will disconnect the main circuit. When the circuit is overloaded, the thermal element of the thermal release will generate heat and bend the bimetallic sheet to push the free release mechanism. When the circuit is under voltage, the armature of the under voltage release is released. It also makes the free release mechanism act.